St Petersburg (Russia), Dec. 22 (Reuters): Russian President Vladimir Putin, a black belt in judo, apparently has the time to contribute to a textbook on the sport in addition to running the worlds largest country.

The Kremlin leader said at the opening of a Toyota car plant in his home town of St Petersburg he had helped make a video on the sport along with a Japanese expert. The two of us recorded a video disc for a judo textbook, he told reporters. I think it will go on sale in January or February.

He thanked Japanese judoka Yasuhiro Yamasita for producing the manual in Russia, but was displeased to learn that he was to coach the Chinese team at next years Beijing Olympics.

Say its not so! Let him come here to coach our team, he said. Our Chinese friends will win everything now. They have home advantage.

Since taking office in 2000, Putin has often been filmed taking part in judo competitions and showing off his physical prowess in other disciplines  including downhill skiing. He played a key role in helping the Russian Black Sea resort of Sochi secure the 2014 Winter Olympics. But judo clearly remains his passion. He said the sport had played a key role in instilling discipline throughout his life.